Golf VI R :: Loud Noise Between 2500 To 3500 After Installation Of Exhaust - Vibration

Recently had an aftermarket turbo back exhaust system installed. After driving for a short while, I noticed that between 2500 and 3500 RPMs the noise was very loud. Once I hit the highway (in which the engine almost exclusively hangs around those numbers), it was almost unbearable to sit in the car while having that constant droning sound. I have had and been in cars with aftermarket exhaust systems before and never heard anything quite like this. It is pretty tame below 2500 and once you hit 4000, it sounds quite nice and that horrible drone goes away. I really trust the shop that did the work, so I doubt it was faulty install. Could it be a faulty design or maybe just the one that I received?

This exhaust is from a reputable maker and they designed this system specifically for the Golf R. I did have some other mods done at the same time (Coilovers, Engine Mount Insert, Intake and a Tune). I know the insert may cause a little bit of vibration and hence a little bit of extra noise, but nothing like this. While driving on the highway at 3000 RPMs, I cannot even clearly see the cars behind me through the rear windshield as there is so much vibration from all the noise.

Forgot to mention, this TBE is resonated with a CAT, so even more reason for concern. Would expect it to be quiet by comparison to a CAT-less non-resonated system